F1 wheel cylinders
 

On our 52 F1 build we are at the brake stage. We started with NOS wheel cylinders where we couldn’t get the bleeder screws to stop weeping. Changed those out to totally new cylinders and those are weeping also. We were really careful on not over tightening, but at a loss as to next steps. Any thoughts on this issue? The brake line connections are dry as a bone.

JB

Re: F1 wheel cylinders
 

loosen and tighten them a few more times---try tighter

Re: F1 wheel cylinders
 

I have not seen that problem, are you sure you are getting them tight enough? I always tighten them down firmly. Your comment "really careful on not over tightening" would tend one to believe that they may not be tight enough. Would be really strange to receive two different cylinders from different sources and have the same problem.

Re: F1 wheel cylinders
 

Are you using silicone brake fluid?
Bruce

Re: F1 wheel cylinders
 

Some of the foreign made products don't get the threads quite right and they can be too loose. There is also a possibility that the tapered seat isn't right. Not a lot can be done if the valve won't seat correctly enough to seal the system. I would try the speed bleeders and see if they will seal it. Wrap the threads with teflon tape if necessary but the valve still has to seat properly.

Re: F1 wheel cylinders
 

I am using dot 3. The cylinders came from vanpelt so guessing they are as good as you can get new. I repeatedly loosened and tightened this afternoon to 9 lbs torque so will see tomorrow if that seated them. Thanks for the advice, I appreciate it.

JB

Re: F1 wheel cylinders
 

I'm trying to imagine it in my head, but 9 lbs ft does not sound very tight to me.

Edit: 5 minutes of googling seems to suggest a figure of around 14ft lbs would be more suitable, but to be honest, it ought to be something you can judge by feel rather than needing a number quoted. I've only ever used a medium sized wrench and hand pressure on bleed nipples. (No sniggering at the back).

Mart.

Re: F1 wheel cylinders
 

Suspect that you are erroneously using torque specs. meant to be applied when using aluminum disc brake calipers with steel bleed screws.
Steel on steel requires a much higher torque value.
Considering that they are 3/8-24 thread size, 25-35 lb. ft. may be more in order.
Tighten them until the weeping stops.

Re: F1 wheel cylinders
 

I've never used a torque wrench on a bleeder valve but my torque on them is likely near 125 Inch/Lbs which is a little over 10 Ft/Lbs. If it won't seal at that then there is a problem with the tapered seat or the bleeder valve taper. Repeated seating of the bleeder valves will burnish the seat & valve somewhat. Too much torque might gall the surfaces. A quick look at a bleeder valve after tight seating, should reveal evidence of seating on the valve taper. It if doesn't seat all the way around then there is a problem.

Re: F1 wheel cylinders
 

They were dry this morning at nine lbs so if they weep again I will run them up a little. Using a torque wrench due to my 10mm bleeder wrench being so long, and unsure of force being used on the hollow screw.

JB

Re: F1 wheel cylinders
 

Wrap them with a little Teflon tape.

Re: F1 wheel cylinders
 

LOL, came home and they were dry. Based on the feedback I ran the torque up to 12!

JB

Re: F1 wheel cylinders
 

Sounds like your on the right track.